PI3K/AKT is a recurrent intracellular module downstream of receptor tyrosine kinases and some GPCRs, linking extracellular cues to metabolism, survival, and growth programs.
What it is
Class I PI3K enzymes generate PIP3, recruiting AKT isoforms to the membrane for activation. The cascade is educationally important because IGF-1, insulin, and many growth pathways converge on it.
How it works
Receptor activation stimulates PI3K, PIP3 production, PDK1/mTORC2-dependent AKT activation, and phosphorylation of downstream targets that regulate glucose handling, protein synthesis cues, and apoptosis thresholds.
PTEN and other lipid phosphatases restrain the pathway, so net output reflects opposing enzymatic activities.
Biological role
PI3K/AKT supports nutrient responses and cell survival signaling across tissues. It also feeds into mTOR networks, which is why these pages are densely cross-linked.
Proteins involved
- PI3K (class I)
- PTEN
- AKT1/2/3
- PDK1
- mTORC2
Research summary
Biochemical and genetic studies define pathway architecture and disease associations. Peptide education should cite PI3K/AKT only when primary sources measure relevant nodes.
Descriptions summarize published mechanistic frameworks. Findings from cell culture or animal models should not be interpreted as proven clinical effects in humans.
Research limitations
Scientific references
- Manning BD, Toker A. AKT/PKB signaling reviews in Cell.
- Fruman DA et al. PI3K pathway surveys.